Ability to import Sparks of all types

I've made six different submission that the user is presented with depending on the content type that they have specified. I've added a multimedia Uri variable into the Spark base class which handles an extra piece of content, specifically for pictures and sounds (because video will be external, see below). The next step, submission, should basically just be composed of using the Uri to upload the multimedia to the Amazon cloud database.

Pictures can be taken or imported from the gallery, sounds can be recorded or imported similarly. For now, with videos the user just gives a link to a youtube video, and there's some simple logic involved to see if the string contains "youtube" or "youtu.be". Links, text, and code, are all handled like text at the moment. 

I've been working successfully in a few spike projects that I haven't yet merged into the STEAMnet/Flynt code yet. I've written ways to get the youtube thumbnail and video title from a link, and a way to get the favicon from a link. Currently working on embedding youtube videos, and having weird glitches.